Microfluidic chip with dielectrophoretic electrodes extending in hydrophilic flow path

Abstract

The present invention is notably directed to a microfluidic chip (1, 1a) comprising: a flow path (22) defined by a hydrophilic surface; a liquid input (24, 24a, 24b) on one side of the flow path; at least one electrical circuit (62), hereafter DEP circuit, comprising at least one pair of dielectrophoretic electrodes (E21, E22), hereafter DEP electrodes, wherein: each of the DEP electrodes extends transverse to the flow path; and the DEP circuit is configured to generate a dielectrophoretic force, hereafter DEP force, at the level of the DEP electrodes. The chip may further include one or more electroosmotic circuits. The present invention is further directed to methods of operation of such a microfluidic chip.

Description

FIELD OF THE INVENTION[0001]The invention relates in general to the field of microfluidic chips. It is in particular directed to microfluidic chips equipped with dielectrophoretic and electroosmotic circuits, e.g., wafer-based fabricated chips having electrodes extending through microstructures thereof.BACKGROUND OF THE INVENTION[0002]Microfluidics generally refers to microfabricated devices, which are used for pumping, sampling, mixing, analyzing and dosing liquids. Prominent features thereof originate from the peculiar behavior that liquids exhibit at the micrometer length scale. Flow of liquids in microfluidics is typically laminar. Volumes well below one nanoliter can be reached by fabricating structures with lateral dimensions in the micrometer range. Reactions that are limited at large scales (by diffusion of reactants) can be accelerated. Finally, parallel streams of liquids can possibly be accurately and reproducibly controlled, allowing for chemical reactions and gradients ...

AI Technical Summary

Benefits of technology

The present invention is a microfluidic chip that includes a hydrophilic surface and at least one electrical circuit for generating a force to move liquid through the chip. The chip has a flow path defined by the hydrophilic surface and includes DEP electrodes and EO electrodes. The DEP electrodes are transverse to the flow path and the EO electrodes are also transverse to the flow path. The chip can also have a microchannel in fluid communication with a liquid loading pad and a capillary pump. The invention also includes a method of operating the chip to detect changes in the liquid. The technical effects of the invention include improved control over liquid movement and detection of changes in the liquid.

Problems solved by technology

While several methods and devices for flowing liquids inside microfluidic flow paths have been developed, these methods either lack flexibility or operate with a limited type of samples and flow conditions.

However, contrary to what is done in semiconductor wafer processing, microfluidics generally have deep structures, i.e., around a few micrometer, up to 20 micrometers or even deeper.

In many cases, 5 micrometers is already considered as a small depth in microfluidic applications because such a small depth can generate a large hydraulic resistance on a liquid and can block or become clogged with microbeads and particles, such a small depth can also be incompatible with samples containing cells.

As a result, existing semiconductor wafer processes are challenged by, if not incompatible with the requirements needed for microfluidic chip fabrication both in terms of manufacturing processes and cost of fabrication.

Images